diff --git a/lib/ddtrace/contrib/faraday/middleware.rb b/lib/ddtrace/contrib/faraday/middleware.rb
index 08f85eaa6be..a5bc3545b56 100644
--- a/lib/ddtrace/contrib/faraday/middleware.rb
+++ b/lib/ddtrace/contrib/faraday/middleware.rb
@@ -55,8 +55,8 @@ def handle_response(span, env)
 
         def propagate!(span, env)
           env[:request_headers].merge!(
-            Ext::DistributedTracing::HTTP_HEADER_TRACE_ID => span.trace_id,
-            Ext::DistributedTracing::HTTP_HEADER_PARENT_ID => span.span_id
+            Ext::DistributedTracing::HTTP_HEADER_TRACE_ID => span.trace_id.to_s,
+            Ext::DistributedTracing::HTTP_HEADER_PARENT_ID => span.span_id.to_s
           )
         end
 
diff --git a/test/contrib/faraday/middleware_test.rb b/test/contrib/faraday/middleware_test.rb
index 09cab53b564..006a8b8d60e 100644
--- a/test/contrib/faraday/middleware_test.rb
+++ b/test/contrib/faraday/middleware_test.rb
@@ -92,8 +92,8 @@ def test_distributed_tracing
           headers = response.env.request_headers
           span = request_span
 
-          assert_equal(headers[Ext::DistributedTracing::HTTP_HEADER_TRACE_ID], span.trace_id)
-          assert_equal(headers[Ext::DistributedTracing::HTTP_HEADER_PARENT_ID], span.span_id)
+          assert_equal(headers[Ext::DistributedTracing::HTTP_HEADER_TRACE_ID], span.trace_id.to_s)
+          assert_equal(headers[Ext::DistributedTracing::HTTP_HEADER_PARENT_ID], span.span_id.to_s)
         end
 
         private